Automatic control of catalyst promoter in a hydrocarbon conversion process



Aug. 8, 1950 J. L. snor-:BE 2,518,307

AUTOMATIC CONTROL 0F CATALYST PROMOTER 1N A muaocmon coNvERsIoN PRocEssINVENTOR. J.L. GROEBE ATTORNEYS ETHYLENE Aug. 8, 1950 J. L. GROEBEAUTOMATIC CONTROL 0F CATALYST PROMOTER IN A HYDROCARBON CONVERSIONPROCESS Filed NOV. 4, 1946 ALKYLATION EFFLUENTA 2 Sheets-Sheet 2 Hyg/wh*ATTORNEYS Patented Aug. 8, 1950 AUTOMATIC CONTROL F CATALYST PBO- MOTERIN A HYDROCARBON CONVERSION PROCESS John L. Groebe, Phillips, Tex.,

Petroleum Company,

assigner to Phillips a corporation of Delaware Application November 4,1946, Serial No. 707,749 9 claims. (c1. 26o-essa) v an added catalyticpromoter, such as the alkylation of isobutane with ethylene to producediisopropyl in the presence of an aluminumchloride hydrocarbon complexcatalyst promoted by a hydrogen halide.

In the catalytic conversion of organic compounds promoters are oftenused to increase the yield of products, the life of the catalysts, etc.

`The conversion of hydrocarbons, such as polymerization, alkylation,hydrogenation, disproportionation and cracking, is frequently eiected inthe presence of a suitable catalyst. For example, in the alkylation of alow-boiling isoparafiin such as isobutane, aluminum chloride, eithersupported on active charcoal, activated alumina or aluminus materialssuch as bauxite, active silica and various clays such as fullers earthand kieselguhr, or as a separate liquid in the form of a complex with anorganic Vor an inorganic compound or material, is used as a catalyst toconvert the isobutane to a hydrocarbon having a diiferent molecularweight. It is often necessary and highly desirable in such a conversionprocess which uses aluminum chloride las a catalyst to have a smallamount of a hydrogen halide present as a promoter, sometimes only fromabout 0.01 to about 1 or about 5 per cent. by weight ofthe hydrocarbonpresent in the reaction zone. Successful operation can be maintainedwith no more than about 0L1 to l per cent hydrogen halide present, aconcentration which canbe adequately maintained with the addition ofonly about 5 to about 10 pounds of hydrogen halide an hour to a reactionsystem producing 65,000 to about 75,000 gallons of product per day.lWater has also often been added to the reaction system as a promoterwhen aluminumchloride is used as the catalyst because f` the waterreacts with a small amount of aluminum chloride'to liberate hydrogenchloride.

Various alcohols, alkyl halides and organic ammonium compounds arefrequently used to promote reactions catalyzed by such catalysts ashydrogen fluoride. Boron trifluoride and titanium tetraiiuoride havebeen used for promoting the alkylation of hydrocarbons in the presenceof a hydroiiuoric acid catalyst. Hydrides of sulfur tellurium andselenium are also promoters and may be used to promote such reaction aspolymerization, desulfurizationand dehydrogenation. Still anotherpromoter is ethylene oxide which is frequently used to promote catalyticcracking reactions.

Since these promoters are eective when present only in an optimumconcentration in the reaction mixture, careful control of theconcentration is required to assure optimum yield of product andprolonged catalyst life. The proper introduction of the promoter intothe reaction zone is a definite and vexatious problem. Continuous or atleast intermittent injection of the promoter into the conversion processis required in continuous systems. As a result of Variation in the feedcomposition and the inevitable variation in the temperature and pressureof the reaction, the amount of promoter injected into the system must becontinually changed to correspond to requirements for a proper yield ofproduct. Such control of the injection of the promoter may be carriedout by analyzing the conversion eilluent to determine the yield ofproduct and then injecting the amount of promoter required as the resultof the conversion ellluent analysis. At the present time, such analysisof the conversion eilluent and the regulation and control of thepromoter to the reaction system are-manually operated and controlled. Itis much to be desired, therefore, to provide a process and apparatusvfor the continuous and automatic injection of a promoter into thereaction system in accordance with immediate requirements.

An object of this invention is to provide a process and apparatus forthe control of the conversion of organic compounds.

It is another object of this invention to provide apparatus and meansfor the continuous and automatic injection of a promoter into a systemfor the catalytic conversion of organic compounds in accordance with theimmediate requirements of thev system. y A further object of thisinvention is to provide a process and apparatus for the conversion oflsobutane and ethylene to diisopropyl in the presence of ahydrocarbon-aluminum chloride complex promoted by a hydrogen halide.

Another object of this invention is to provide a process and apparatusfor injecting a. promoter into the reaction system yof a process for theconversion of hydrocarbons.

Still another object of this invention is to alkylate alkylatablehydrocarbons.

It is still a further object of this invention to react watercontinuously and automatically with a liquid hydrocarbon-aluminumchloride catalyst to produce a small controlled amount of hydrogenchloride.

Further objects and advantages of the present invention will becomeapparent to those skilled in the art from the accompanying descriptionand disclosure.

According to this invention, a iiuid promoter is injected into thereaction system of a process for the conversion of organic compounds toa prod-v uct having a different molecular weight than the reactant orreactants by means photoelectrically responsive to the composition ofthe conversion eiliuent. More specifically, a fluid promoter isintroduced into the system of a conversion process in a. continuous andautomatic manner andv in the required amount by creating an electricalimpulse corresponding to a particular analysis of the conversioneilluent. which electrical impulse is created by means of an infra-redanalyzer, such as that manufactured by Baird Associates. The conversioneiliuentis passed in the vapor phase through such an infra-red analyzerand the resulting electrical impulse produced in the photoelectricallyresponsive portion of the analyzer is picked up and amplied by asuitable amplifying system. The amplified impulse operates a'.conventional recorder-controller, such as that manufactured by Leeds andNorthrup Company or by Brown Instrument Company, whichrecorder-controller, in turn, operates a Dump or a valve or both for thecontinuous injection of a promoter into the reaction system.

The invention will be described in more detail "in connection with theaccompanying drawing which shows diagrammatically arrangements ofapparatus which can be used in practicing an embodiment of thisinvention. Figure 1 shows diagrammatically an arrangement of apparatussuitable for the alkylation of an alkylatable hydrocarbon with an olefinhydrocarbon. Figure 2 shows diagrammatically an arrangement of apparatusfor the automatic injection of a promoter into such a process as shownin Figure 1. Although the drawings and the description thereof arelimited specically to the alkylation of isobutane with ethylene and tothe injection of Water in a particular manner to promote the reaction,the description and drawing should not be construed to 'unnecessarilylimit the invention.

Referring to Figure 1, the operation and apparatus will be vdescribed inconnection with the alkylation of isobutane by reaction with ethylene toproduce an alkylate fraction containing primarily the hydrocarbon knownas diisopropyl (2,3-dimethylbutane). Isobutane is passed to the processthrough pipe I0 and an ethylene-containing stream is passed to theprocess through pipe I I. As will be appreciated by those skilled in theart in commercial operation, each of the streams in pipes I0 and II willgenerally containappreciable amounts of other hydrocarbons as well andthis will apply particularly to the ethylene-containing stream. Theethylene-containing stream will generally include ethane and may alsoinclude isobutane since it is often the practice to use liquid isobutaneas an absorption liquid to separate an ethylene rich material fromeiuents of dehydrogenation processes. The alkylation reaction ispreferably conducted in two reactors, I2 and I3, each of which isprovided with a suitable mixer I4 of which the essential components area motor and a stirrer within the alkylator. The stirrer is driven by themotor at a speed such that intimate mixing is .obtained between thecomplex catalyst and the hydrocarbon reaction mixture, which in thisinstance is primarily in the liquid phase, although vapor phaseoperation is broadly within the scope of this invention.

The two yalkylators, I2 and I3, are connected by apipe I5 so that theyoperate in series as substantially a single alkylation zone. Ethyleneintroduced through pipe II is admixed with isobutane introduced throughpipe I0 and a desired portion thereof enters the bottom of alkylator I2.A liquid hydrocarbon-aluminum chloride complex is introduced near thebottom of alkylator I2 through pipe I6. If desired, a portion of theethylene stream may also be added to the mixture in alkylator I2 throughpipe I'I near the top of the alkylator. The reaction temperature shouldbe between about 110 and about 120 F. and the pressure should besuicient to maintain the hydrocarbon in the liquid phase, which in thisinstance will be between about 400 and about 420 pounds persquare inchgage. The ratio of isobutane to ethylene in the combined feed should beat least about 2:1 and, while it may be as high as 10:1 or more,satisfactory operation will generally be obtained at a ratio of about3:1 provided a suiiicient amount of recirculation of reaction mixture isused.

A reaction mixture inI alkylator I2 passes from the top thereof throughpipe I5 to the bottom of alkylator I3. If desired, an additionalquantity of an isobutane-ethylene mixture may be added through pipe 23to the reaction mixture just before it enters alkylator I3. A reactioneliluent from alkylator I3 is. removed therefrom and passed through pipe2l to a settler 22. In order to control the amount of promoter inalkylators I2 and I3, a portion of the eluent in line 25 is continuouslywithdrawn therefrom and passed through pipe 6I to a iiash chamber 62, inwhich chamber at least a, portion of the liquid eiluent is vaporizedunder conditions of constant temperature and constant pressure. A liquidbottom fraction is removed from ash chamber 62 through pipe 64 and avapor overhead fraction is removed from chamber 62 through pipe 63. Thisvapor fraction is continuously passed through pipe 63 and through aninfra-red analyzer 90. In some instances it may be desirable to vaporizeall of the eiliuent passing through pipe 6I to chamber 62. In suchinstances, no liquid will be withdrawn from ilash chamber 62 throughpipe 64. Infra-red analyzer creates an electrical impulse correspondingto the composition of the vaporous stream passing therethrough, whichimpulse is amplified by a conventional amplifier IOI and the amplifiedimpulse is passed to a conventional recorder-controller |02. Usuallyamplier IOI also comprises a phase inverter to change the alternatingcurrent created in the infra-red analyzer 90 to a direct current.Conditions of temperature and pressure in vaporizer or ash chamber 62are maintained constant so that the composition of the overhead vaporwill vary only with the composition of the eil'luent in pipe 25 and willnot vary because of variations in temperature and pressure in chamber62. Usually chamber 62 is maintained at abisso? atmospheric `pressureand at a-temperature of v passed through vpipe 40, a pump'g4I, pipe42 to`pipe 24. .A hydrocarbon-aluminum chloride coms plex catalyst is beingrecycled through pipe 24 to alkylator |2 by meansof a pump 36 and pipe.

I6.l Upon the introduction of water from pipe 42 into pipe 24, hydrogenchloride is. liberated vfrom the aluminum chloride complex and serves asa promoter for the alkylation reaction. Valve |06 is set such that theoptimum amount of hydrogen chloride is liberated by the water in pipe 24in response to the composition of the eiiluent flowing from alkylator I3through pipe 25. The mechanical and electricalA features for theoperationpof valve |06 in response to the composition of the effluent inpipe will be more fully describedl hereinafter with regard to Figure 2.

Settler 22 is preferably an elongated receptacle set on a slope with asolid baille plate (not shown) near the inlet and extending about halfup in thev settler. Such a baille plate serves to distribute theincoming emulsion across the receptacle sectionthereby tending to reduceany short-circuiting effect and also serving as a retainer wall for theliquid catalyst which settles out. The liquid complex catalyst whichsettles out is removed from settler 22 through pipe 24 and thehydrocarbon material substantially free from catalyst is passed fromsettler 22 to pipe 25.

A substantial portion of this hydrocarbon material is passed from pipe2li/through pipe 26 to a cooler I8 where it is cooled to an extentsufficient to compensate for the heat of reaction generated inalkylators I2 and I3 and to maintain a desired reaction temperaturetherein. This portion of the hydrocarbon material is then recycled bymeans of pipe |9 to pipe I0 of alkylator I2.

The other part of the hydrocarbon material is passed through pipe 25 toa separating means 30. Generally, it will be desirable to wash thehydrocarbon material with an alkaline solution to remove any acidicmaterials which may be present before the material is subjected tofractional distillation. Separating means will comprise 'necessaryequipment for such a washing and suitable fractional distillationequipment such as is common in such alkylation plants. A diisopropylfraction is Lseparated and removed from separating means through pipe 3|as a product ofthe process. Unreacted-isobutane is recovered `andremoved from separating means 30 through pipe 32 and returned to theprocess by being introduced into pipe I0. Normal butane, which willinclude that initially accompanying the charge stock and any normalbutane formed by isomerization during the alkylation process'.

t may be separated and discharged through pipe 33. One or more of thealkylate fractions may also be recovered through pipe` 34. Undesiredlight gases are discharged through pipe 35. f

' The liquid hydrocarbon-aluminum chloride complex catalyst whichsettles from the effluents of the alkylation zone is passed from' a'lowpoint of settler 22 through pipe 24 and pump 36 and then through pipe`I6 back to alkylation zone I2. To this` recycledliquid complexcatalyst, water is added in small continuous and controlled i knownquantities.. preferably just beforethe intake of pump 36. This canbeaccomplished as previously described by introducing water through pipe3l to tank 38. The water is withdrawn therefrom through pipe 40, passedthrough pump 4| and pipe 42 and. introduced into pipe 24 into thecatalyst passing therethrough by a nozzle (not shown) extending insidepipe24, approximately to the center line. In many instances, pump 4|will be Aa centrifugal pump and valve |06 will be. suitable forregulating the flow of water through pipe'l2.

In making the original batch of catalyst, kerosene or other suitablehydrocarbon material may be added through pipe l5 to catalystpreparation vessel 46. Aluminum halide or other Friedel- Crafts metalhalide catalysts, such as aluminum chloride, is added to vessel 4Ethrough line dl. These materials are intimately mixed by means of amixer 48 in vessel 46. The resulting liquid hydrocarbon-aluminumchloride complex is introduced into the alkylation system through pipe49 and pipe 24. After the process has been started the activity of therecycled catalyst may be maintained by refortifying it by passing aportion of this recycled catalyst through pipe 50 to vessel 6 whereinaluminum chloride either as such or ass an aluminum chloride complex maybe intimately mixed with it. If it is desired to add an aluminumchloride complex, such may be formed bypassing heavy .hydrocarbons frompipe 34 through pipe 60 to pipe 45 into catalyst preparation vessel 43.Since such a treatment tends to increase the total volume of catalystavailable, it will generally be found necessary to maintain the desiredvolume of catalyst by withdrawing material from the system through pipe24 and pipe 5|. It has been found that the viscosity of the catalyst canbe more easily maintained at a low value by having the catalystJ admixedwith an appreciable amount of alkylatable hydrocarbons in the absence ofan olefin outside thereaction zone. To this end isobutane may be addedto the catalyst in pipe 24 by being passed from pipe I0 through pipe 52.In case it is desired to mix the catalyst passing through pipe 49 withisobutane, this is accomplishedby passing isobutane from pipe I0lthrough pipe 53 to pipe 49.

In many instances it may be desirable to inject hydrogen chloride orother hydrogen halide into.

pipe 24 instead of injecting water therein. In such modifications, pipe42 and valve |06 will be operated to control the amount of hydrogenchloride introduced into pipe 24. Hydrogen chloride or other promotermay also be introduced directly (notshown) into the alkylator I2 andvalve |06 y will thus control the injection ofhydrogen chloride directlyinto the alkylator without departing from the scope of this invention.It is also i possible that valve |06 may constitute a series of valvesfor the multiple point injection of a promoter into the reaction zone.Other similar modifications may be practiced without departing from thescope of this invention.

Aluminum chloride is the Friedel-Crafts metal halide catalyst which willmost generally be used in the practice of this invention when applied tothe process described in Figure l. Within the broad concept of thisinvention, aluminum bromide and aluminum fluoride may also be used asthe catalyst. While aluminum fluoride generally does not -givesatisfactory results, mixed halides, such as AlClzF, AlClFz, AlBreF, andthe like, may also be used successfully. Liquid hydrocarbonaluminumhalide catalyst is generally prepared .by reacting `a relatively pureandlsubstantially anhydrous aluminum halide with a parailln hyl7drocarbon or a paramn hydrocarbon fraction at a temperature betweenabout 150 and about 230 F. It is often desirable to eiect the productionof the catalyst in the presence of a small amount of a hydrogen halidewhich may be added during its formation. The hydrocarbon and aluminumchloride are vigorously mixed until a resulting complex contains incombination from' about 40 to about 'I0 weight per cent of aluminum matecontact during the period the catalyst is being prepared. Twogeneraltypes of catalyst have been prepared. These are characterized ashigh-aluminum halide and low-aluminum halide types. When preparing acatalyst with aluminum halide.' the high aluminum chloride type contains80 to 85' per cent by weight of aluminum chloride. The low aluminumchloride type contains about 55 per cent by weight of aluminum chloride.The high aluminum chloride type can be added during continuous runs insmall amounts to the recirculating catalyst in order to maintaincatalyst activity. In most operations the activity of the catalyst cangenerally be adequately maintained, as to its aluminum halide content,by mixing aluminum halide directly with a suitablel portion of recycledcatalyst complex.

The regulation and control of the introduction of the promoter to theconversion zone of such a system as described in Figure 1 will now bedescribed more fully with reference to Figure 2 of the drawings. Aconversion efliuent passing through pipe 25, such as the alkylationeluent of the process described in Figure 1, is divided into twostreams, usually the larger portion is passed to separating means ofFigure 1 and a minor portion is passed through pipe 6| to a flashchamber 62. In ash chamber 62 a liquid effluent is atleast partiallyvaporizeci under constant conditions of temperature and pressure andvapor is passed from vessel 62 through. pipe 63 and through analysischamber 6B of an infra-red analyzer. Liquid may be withdrawn from flashchamber 62 through line 64. It is important that the condition oftemperature and pressure of flash vessel 62 be maintained constant inorder that the composition of the overhead in pipe 63 will not dependupon the conditions existing in vessel 62 but will depend primarily uponthe'composition of the alkylation elliuent in line 25. In some instancesthe entire portion of the eluent passing through. line 6l may bevaporized in flash chamber 62. `When the entire eluent is vaporized,constant conditions of temperature and pressure in ilash chamber 62 arenot so important because the composition in line 63 cannot changebecause of variations in temperature and pressure in vessel 62. Also,vaporizer 62 may be omitted 4and a liquid may be passed directly frompipe 25 to analysis chamber 66, or, when the material in pipe 25 or asimilar effluent conduit is a vapor, vapor may be passed directly tochamber 66. Of course, when the eflluent in pipe 2| does not include thecatalyst. such as when using i en bolometers 9| and 92.

a solid catalyst in situ, pipe 6| may be connected directly to pipe 2|instead of pipe 25.

The number of chambers and their positions in the infrared analyzer asshown are typical of triple-cell units designed for the analysis ofgaseous or liquid materials. Such units may be purchased on the marketand may be connected up in the manner herein described. In the preferredembodiment of this invention, chambers 18 and 86 of a typicaltriple-cell unit infra-red analyzer are not used. Chamber 66 has acontinuous stream of material to be analyzed passing therethrough andout through line 8|. Chamber.82 is lled with a standard sample of agaseous mixture (or liquid as the case may be) of hydrocarbons ofthe'composition according to the optimum yield of product. such as theoptimum composition of the alkylation ellluent passing through line 2|of Figure 1.

According to Figure 2, light source 68 is a nickel-chromium wire whichglows at about a dull red heat. Light rays from source 68 may passthrough a quartz window 16, if desired, for the purpose of removinginterfering rays of light.

Window 16 is optional and is unnecessary inmany applications of theinstrument. After passing through quartz window 16, the light isdeilected on concave focal mirrors 69 and 1| along paths 'I4 and 13,respectively. In this manner, two light paths for passing throughchambers 66 and 82 are formed. As previously discussed, chamber 82contains a sample of the optimum composition of the elliuent in line 2|.Chamber 66 contains a continuous stream of the eiliuent in line 2|. Inone type instrument, such as the Baird Associate Instrument. the samplechambers areconstructed of brass and silver plated both inside and out.The windows 83,`through which a light beam enters and leaves thechamber, are formed `from sodium chloride. However, calcium chloride hasbeen used in other instruments.

In the application of the present invention to the process described inFigure 1, the ethylene content of the alkylation eiiiuent is of primaryimportance and it is the composition of the ethylene in the alkylationeilluent which is aiected by the promotor. Therefore, the overhead fromash chamber 62 will comprise ethylene along with other low-boilinghydrocarbons. Where the alkylation is of isobutane with ethylene, atypical or optimum alkylation eiuent corresponding to this type ofalkylation and to the particular feed composition used, is scrubbed withsulfuric acid to remove the ethylene therefrom and the remaininghydrocarbons are placed in chamber 82 as a standard sample for theinfra-red analyzer. Inl the event operating conditions on the alkylationunits are changed, such as an increase or decrease in the parailin toolefin ratio, it may be necessary to provide a new control samplerepresentative of the eilluent for chamber 82. Such a procedure may benecessary in order to maintain the proper base or zero line on theinstrument because the changes in the percentages of the various normalparailins will affect the light transmission. The light beams passingthrough chambers 66 and 82 are focused A bolometer is a resistancethermometer formed by wrapping wire, such as platinum or nickel wire,around a strip of mica and coating the whole assembly`with platinumblack. The entire bolometer mecha- `nism actually consists of two suchresistance thermometers 9| and 92 which receive the lighttransmittedthruih sample chamber 66 and reftransformer 93. Resistances96 and 91 comprise the other two arms of the bridge. In operation,

that is with the unknown sample in chamber 66 and the standard sample inchamber 92, the unbalance oi the alternating current bridge caused bythediierence `in light intensity on the two resistance. thermometers .9|and 92` causes., an electrical impulse `of a certain magnitude to flowwhich is picked up at point 98 and is transmitted by suitable means tothe grid of an input tube of a conventional electronic amplifier |0|.The light intensity on bolometers 9| and 92 decrease their` resistanceto the iiow of current therethrough.

The electronic amplifier of |0| maycmprise a single or a series ofvacuum tubes having an anode andl cathode circuit. Incorporated as apart of electronic ampliiier |0| is also a phase inverter to convert thealternating current from 98 to a direct current signal which drivesconventional recorder-controller |02. The phase inverterA mayconveniently comprise an electron discharge rectifying tube having ananode-cathode circuit. Various conventional methods known to thoseskilled in the art may' be used for connecting the electronic ampliiier|0| to the output from the infra-red analyzer and for connecting therecorder-controller |02 to Ithe electron amplifier 0|. In the particularcase shown in Figure 2, a single wire is connected between adjustableresistance 98 and the grid of the input tube of amplifier and since bothtransformer 93 and the input tube of amplifier |0| are grounded (notshown) the circuit is complete. The alternating currentsignal from theresistance bridge or output 98 of the infra-red analyzer is of a verylowE. M. F. and must be amplified by electronic ampliiier |0| to the orderof about l0 to about 20 millivolts, which is sufdcient to driveconventional recording controlling instruments such as the BrownElectronic Recolder-Controller or the Leeds and Northrup Micromax. Theoutput of ampliiier |0| is connested to the thermocouple inputconnection on the recording-controlling instrument by two wires, such asfrom the anode and cathode of the output tube which acts in a similarmanner as a thermocouple. A suitable resistance may be interposedbetween amplifier |0| and recordercontroller |02, if necessary. It isusually necessary to calibrate the strip chart on the recordercontrollerto ascertain the so-called zero or base line near the center of thechart'scale. The sensitivity of the instrument is then adjusted so thata given departure of an inch or so on the chart above or below the baseline produces the desired magnitude of control effect. Valve |06 on line|01 is responsivethrough transmission means |03 to controller |02.Transmission means |03 may comprise either electric or pneumatic means.In case of pneumatic transmission a cam is placed on the shaft of theslide wire disc of controller |02 which cam regulates the airsuppiythrough a pilot. valve to valve |06. A typical hook-upbetween aMicromax controller and an automatic valve on a pipe and one which issuitable for the:

present invention is shown in detail in Folio N-OOB of the Leeds andNorthrup Company.

Water is introduced into water tank 38 through pipe 31 and flowstherefrom through pipe 40 and constant displacement pump |08 and pipe 42into aluminum chloride complex pipe 24 of Figure 1.

Valve |06 regulates the flow of water through bypass line |01; thus,regulating the ow 0f water into aluminum'chloride complex line 24.lValve |06 cannot be placed directly on pipe 42 since pump |08, as shownin Figure 2, is a pitive displacement pump. 'I'he regulation of theamount of water passing' through pipe 42 is accomplished by regulatingthe amount of water by-passed through pipe |01.:

4'I'he injection of water into the aluminum chloride catalyst generateshydrogen chloride which controls the activity of the catalyst. In thediagram of. Figure 1 the control of the `activity of the catalyst ismaintained so that the conversion of the ethylene is about 95 to 97 percent. Lower conversions on the order of 90 to 92 per per cent ofdiisopropyl in the alkylate but gens erally the higher conversion of 95per cent or more ride which increases the conversion of ethylene.

When. the conversion is too high the reverse process is eiected andvalve |09 is closed to decrease the amount of water in line 20.

Thenumber of chambers in the infra-red analyzer, such as chamber 18 andchamber 96 is dependent upon the speciiic applicationof the infra-redanalyzer, that is the number of interfering hydrocarbon components inthe stream which is to be analyzed. In some instances, chamber 19 willcontain the unknown sample while chambers 66, 82 and 86 may be iilledwith some speciiic hydrocarbon which would absorb interfering" lightwave lengths resulting in the intensification of the wave lengths of thedesired Chambers 18 and 86 have windows l components. 19 and 81,respectively, for the transmission of the light rays therethrough. Aspreviously discussed, the arrangement of the chambers and thelcomponents placed in these chambers may be varied without departingfrom the scope of this invention.

Erample As an example of the operation of my invention, an isobutanefeed stock is charged to an apparatus such as is 'illustrated in Figurel, through pipe l0. This stream has a composition such as is shown inthe accompanying table, and is charged in a continuous stream in anamount averaging about that indicated. An isobutaneethylene mixture isprepared by using a liquid isobutane stream, from the same source as theisobutane feed, as an absorption liquid in a demethanizer to which ischarged. as a gas, an efliuent stream from a process for converting anethane-propane mixture to ethylene. This isobutane-ethylene mixturehas'a composition as shown in the table and is charged in about theamount shown, through pipe The reaction temperature ranges up to about140 F. as a maxirnurn,l with a preferred range between and 110 F., andthe volume of cooled recycle passed through cooler I8 and pipe I9 issuch that the overall temperature rise is not more than about 15 to 20F. Under these conditions liquid phase operation is assured with apressure not greater than about 400-420 pounds per square inch gage.

The efiiuent is passed through pipe 2l to settler 22, and catalyst-freehydrocarbon is divided into two portions as shown in the table. Thecatalyst, in an amount between labout 91,500 and 97,000 barrels per day,is separated and the major portion is returned. To this is added, duringnormal operation, about 0.6 gallon of water per hour, through pipe 42.This water is successfully added continuously by automatic injectioninto line 24 of the exact amounts of water` at any particular time asthe result of the infra-red analysis of the eilluent and pneumaticoperation/of ow valve i06 responsive to recorder-controller |02. In)

` addition, aluminum chloride is added to the recirculated catalyst bywithdrawing a side-stream through pipe 50 of about 5 gallons per minute.Aluminum chloride is added, normally, through pipe 41 at about 145 to230 pounds per hour, and intimately admixed in tank 46 with thiswithdrawn catalyst portion, and the refortfied catalyst is returned tothe reaction system through pipe 49. Under these conditions the amountof HCl is maintained at a definite, desired low value and the viscosityof the catalyst is maintained at less than 200`centistokes at 100 F.

I claim: y t

1. In a process for lthe alkylation of an alkylatable hydrocarbon withan olefin in the presence of an alkylation catalyst which is promoted bythe presence of a minor amount of a hydrogen halide in the reactionmixture, the method for continuously controlling the extent ofalkylation which comprises passing infrared light rays through thealkylation eiluent under conditions such that an electrical impulse isproduced corresponding in magnitude to the concentration of unreactedolen in said eiiluent and automatically controlling the amount ofhydrogen halide present in said reaction mixture in response to theAmagnitude of said electrical impulse.

2. In a process for the alkylation of isobutane with ethylene in thepresence of an aluminum chloride-containing catalyst which is promotedby injecting a minor amount of hydrogen chloride into the alkylationzone and in which the ratio of isobutane to ethylene in the feed isbetween about 2:1 and about 10:1, the method for continuouslycontrolling the extent of alkylation which comprises passing infraredlight rays through the alkylation eilluent under conditions in saidemuent and automatically controlling the amount oi' hydrogen chlorideinjected into said alkylation zone in response to said electricalimpulse; said hydrogen chloride being injected in increased amounts whenthe ethylene content of said eiiluent is above a pre-determined amountand said hydrogen chloride being injected in decreased amounts when theethylene content of said eiiluent is below a pre-deterxnined amount.

3. In a process for the alkylation of isobutane with ethylene in thepresence of an aluminum chloride-containing catalyst which is promotedby injecting a minor amount of a hydrogen halide into the alkylationzone and in which the ratio of isobutane to ethylene in the feed isbetween about 2:1 and about 10:1, the methodr for continuouslycontrolling the extent of alkylation which comprises passing infraredlight rays through the alkylation eilluent under conditions such that anelectrical impulse is produced corresponding to the concentration ofethylene in said eiliuent and automatically controlling the amount ofhydrogen halide injected into said alkylation zone in response to saidelectrical impulse so as to maintain a conversion of ethylene of fromabout to about 97 per cent.

4. The process of claim 2 in which the concentration of ethylene in saidalkylationeiiluent is maintained between about 3 and about l0 per centof the ethylene introduced as feed to the alkylation zone.

5. The process of claim 2 in which the hydrogen halide is introducedinto said alkylation zone by introduction of water with said catalyst.

6. In an alkylation process comprising reacting a mixture comprisingisobutane and ethylene in a molar ratio of between about 2 to l andabout l0 to l in an alkylation zone under alkylation conditions in thepresence of an aluminum chloridecontaining catalyst refortifled duringalkylation and promoted with hydrogen chloride wherein the catalystactivity and alkylating eiiiciency thereof are dependent upon theconcentration of hydrogen chloride in said alkylation zone, the methodof continuously maintaining the ethylene concentration in the alkylationefiluent between about 3 and about 5 per cent of the ethylene in saidreaction mixture, which comprises passing infrared rays through at leasta portion of said alkylation eiiluent under conditions such that anelectrical impulse is produced corresponding in intensity to theconcentration of ethylene in said eilluent and automatically regulatingthe concentration of hydrogen chloride in said alkylation zone inresponse to variations in intensity of said electrical impulse so as tomaintain said ethylene concentration.

'7. The process of claim 6 wherein the hydrogen chloride concentrationin the alkylation zone is regulated by the controlled introduction ofwater to the catalyst-reaction mixture.

8. An alkylation system for the alkylation of anA alkylatablehydrocarbon with an oleiln in the presence of an aluminumhalide-containing catalyst promoted with a fluid promoter andsimultaneously controlling the extent of alkylation by automaticallyregulating the concentration of said promoter in the alkylation zone inresponse to variations in the concentration of oleiin in the alkylationeffluent, comprising in combination an alkylation chamber having a feedinlet conduit communicating with said chamber, a catalyst inlet conduitcommunicating with said chamber, and an eilluent conduit communicatingwith said chamber; a iluid promoter feed line communicating with saidchamber; a ash chamber for the tween said alkylation chamber and saidash chamber; conduit means for passing vapor from said flash chamber tosaid infra-red analyzer; means for transmitting the amplified impulsefrom said amplication system to said recordercontroller; andtransmission means communicating between said recorder-controller andsaid control valve for automatically operating said valve in response tothe magnitude of the electric impulses created in said infra-redanalyzer.

9. An alkylation system for alkylation of an alkylatable hydrocarbonwith an oleiin in the presence of an aluminum halide-containing catalystpromoted with a iiuid promoter and simultaneously controlling the extentof alkylation by automatically regulating the concentration of M saidpromoter in the alkylation zone in response to variations in theconcentration of olefin in the alkylation eiiiuent, comprising incombination an alkylation chamber having a feed inlet line, a iiuidpromoter inlet line, a catalyst inlet line, and an eiiluent line; a flowcontrol valve in said4 promoter line for regulating flow of promotertherein; and means for actuating said flow control valve comprising aninfra-red light source, light transmission means in communication withsaid eilluent line and adapted for passage of light from said lightsource therethrough, an electrically energized element positioned so asto receive light from said transmission means and in actuatingcommunication with said control valve.

JOHN L. GROEBE.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PA Date

1. IN A PROCESS FOR THE ALKYLATION OF AN ALKYLATABLE HYDROCARBON WITH ANOLEFIN IN THE PRESENCE OF AN ALKYLATION CATALYST WHICH IS PROMOTED BYTHE PRESENCE OF A MINOR AMOUNT OF A HYDROGEN HALIDE IN THE REACTIONMIXTURE, THE METHOD FOR CONTINUOUSLY CONTROLLING THE EXTENT OFALKYLATION WHICH COMPRISES PASSING INFRARED LIGHT RAYS THROUGH THEALKYLATION EFFLUENT UNDER CONDITIONS SUCH THAT AN ELECTRICAL IMPLUSE ISPRODUCED CORRESPONDING IN MAGNITUDE TO THE CONCENTRATION OF UNREACTEDOLEFIN IN SAID EFFLUENT AND AUTOMATICALLY CONTROLLING THE AMOUNT OFHYDROGEN HALIDE PRESENT IN SAID REACTION MIXTURE IN RESPONSE TO THEMAGNITUDE OF SAID ELECTRICAL IMPULSE.